The 7 Roman Numeral Symbols
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. The letters derive from Etruscan tallying marks and were standardized by the Romans across their empire for commerce, dates, and architecture.
Subtractive Notation Rules
When a smaller numeral appears before a larger one, subtract it: IV = 4 (not IIII), IX = 9, XL = 40, XC = 90, CD = 400, CM = 900. Rules: Only I, X, and C can be used subtractively. Only subtract from the next two higher values (I before V and X only; X before L and C only; C before D and M only).
Modern Uses of Roman Numerals
Super Bowl numbering (Super Bowl LVIII). Movie sequel titles (Rocky IV, Star Wars Episode VII). Clock faces (often use IIII instead of IV for visual balance). Copyright years in film credits. Monarch and pope numbering (Henry VIII, Pope Francis I). Outline headings in formal documents.
Quick Conversion Examples
2024 = MMXXIV. 1999 = MCMXCIX. 42 = XLII. 888 = DCCCLXXXVIII (longest standard Roman numeral). 3999 = MMMCMXCIX (largest standard Roman numeral).